I have not worked on that type of movement, however have worked on a few W&H 1/4 strike movements, therefore others may know better how to set this one up, that said here is my take on what is happening.
I think someone has messed with the levers.
What I can gather from your video is that the top lever (the one that drops onto the cam with 4 sections cut out) is dropping to far as you should only have 1 x bim-bam at the 1/4 past the hour, however the rack teeth are dropping to 5 places, the 1/2 hour it is dropping 6 places and should only be dropping 2 the 3rd quarter is 7 places and should only be dropping 3 teeth on the rack.
Test the lever to see if it is easy to move as I think someone has moved it up (closed the V).
First thing is to adjust the cam so that the lever pin hits the middle not the far right as you have it now.
Then if you turn to the 1/4 past the hour and open the lever so that when it drops it only lets '1' rack tooth fall, if I am correct the rest should now drop 2, and 3 rack teeth as you continue to move the minute hand around the face.
On the hour it does not bim-bam, however the lever that controls this is cut off at the bottom of your video, therefore put up another video where we can see the whole of the movement in action.